Fix Julian weekday display in mobile mode

jcal/public/index.html

@@ -55,8 +55,8 @@
                     href="https://en.wikipedia.org/wiki/Gregorian_calendar">Gregorian
                 calendar</a>, forms the basis of civil calendar in most countries.</p>
             <p>Julius Caesar (with aid of Sosigenes of Alexandria) introduced this calendar to replace the earlier Roman
-                calendar, which required manual addition of leap months to keep it in synchrony with the
-                seasons.Unfortunately, it had leap days every four years without question, resulting in the average year
+                calendar, which required manual addition of leap months to keep it in synchrony with the seasons.
+                Unfortunately, it had leap days every four years without question, resulting in the average year
                 having 365.25 days. However, the actual tropical year is roughly 365.2422 days, resulting in the Julian
                 calendar gaining a day every 129 years. This means that seasons drift, starting earlier and earlier in
                 the year.</p>

jcal/src/Calendar.tsx

@@ -41,7 +41,7 @@ function Day({year, month, day, todayJDN}: DateProps & { todayJDN: number }): JS
     const jdn = julianJDN(year, month, day);
     return <div className={`Day NormalDay ${jdn === todayJDN ? 'Day-today' : ''}`}>
         <div className="Day-name">{day}</div>
-        <div className="Day-weekday">{weekdayNames[(day - 1) % 7]}</div>
+        <div className="Day-weekday">{weekdayNames[(jdn + 1) % 7]}</div>
         <DayDetail jdn={jdn}/>
     </div>;
 }